mylittlespacemuseum
Gemini 5 Flown S-8/D-13 Checklist Page
This is the reverse of the before shown page. It indicates when the experiment should be conducted.
The annotations were done during the flight.
Due to some changes in the mission not all oberservation were made.
The Gemini 5 mission report describes the results of the experiment as follows:
"8.15.1 Objective
The first objective of experiment S-8/D-13 was to measure the visual acuity of the flight crew members before, during, and after long-duration space flights in order to ascertain the effects of a prolonged spacecraft environment. The second objective was to test the use of basic visual-acuity data combined with measured optical properties of ground objects and their natural lighting, the atmos- phere, and the spacecraft window to predict the limiting naked-eye visual capability of the flight crew to discriminate small objects on the surface of the earth in daylight.
8.15.2 Equipment
The experimental equipment consisted of an in-flight vision tester for testing visual acuity, an in-flight photometer to monitor the space- craft window s and test patterns at two ground observation sites.
8.15.2.1 In-flight vision tester.- The in-flight vision tester was a small, self-contained binocular optical device containing a transilluminated array of 96 high-contrast and low-contrast rectangles, half of which were oriented vertically in the field of view while the remainder were horizontal. Rectangle size, contrast, and orientation were randomized; the presentation was sequential, and the sequences were non-repetitive. Each rectangle was viewed singly at the center of a 10° adapting field the apparent luminance of which was approximately i00 foot-lamberts. Both members of the flight crew made forced- choice judgments of the orientation of each rectangle and indicated
their responses by punching holes in a record card. Optical alinement was accomplished by means of a bite-board equipped with the flight crew member's dental impression. Electrical power for illumination within the illumination was derived from the spacecraft.
8.15.2.2 In-flight photometer.- A photoelectric photometer was mounted near the lower right corner of the right hatch window to measure the amount of ambient light scattered by the window into the path of sight at the moment when observations of the ground test patterns were to be made. The photometer had a narrow (1.2°) circular field of view into the opening of a small black cavity a few inches away from the outside of the right hatch window. The photometric scale was linear and extended from 60 to 9000 foot-lamberts. Since the apparent luminance of the black cavity was always less than 60 foot-lamberts, any reading of the photometer was ascribable to ambient light scattered by the window. This information combined with data on the beam transmittance of the window and on the apparent luminance of the background squares in the ground array, enabled the contrast transmittance of the window at the moment of observation to be calculated.
8.15.2.3 Ground observation sites.- Ground observation sites were provided on the Gates Ranch 40 miles north of Laredo, Texas, and the Woodleigh Ranch 90 miles south of Carnarvon, Australia. At the Texas site, twelve 2000 by 2000 feet squares of plowed, graded, and raked soil were arranged in a 4 by 3 matrix. White rectangles of styrofoam-coated wallboard were laid out in each square. Their length decreased in a uniform logarithmic progression from 610 feet in the northwest corner (square number 1) to 152 feet in the southwest corner (square number 12) of the array. Each of the 12 rectangles was oriented in 1 of 4 positions (i.e., north-south, east-west, or diagonal) and the orientations were random, within the series of 12. Advance knowledge of the rectangle orientations were withheld from the flight crew since their task was to report the orientations. Provision was made for changing the rec- tangle orientations between passes and for adjusting their size in accordance with anticipated slant range, solar elevation, and the visual performance of the flight crew on preceding passes.
8.15.3 Procedure
Both of the flight crew members completed five or more preflight sessions in a laboratory training van during which they became experienced in psychophysical techniques and established physiological base- lines descriptive of their individual visual performance. The statistical fluctuations in that perfomance were established, providing a means by which the ground pattern observations could be interpreted.
8.15.4 Results
In-flight vision tests were to be performed once each once by each crew member. Ground observations were to be made by the pilot with the command pilot orienting the spacecraft as prescribed in the flight plan. The results of these tests, together with preflight and postflight test results, are shown in figure 8.15-1. Unfavorable cloud conditions caused some scheduled observations of the ground markings to be deleted. In the latter part of the mission, lack of thruster control made observation of the ground patterns impossible.
Quantitative observation of ground marking was achieved only once. This occurred at the ground observation site near Laredo, Texas, during revolution 48. Despite the fleeting nature of the observation, there exists a reasonable probability that the pilot correctly discriminated the rectangles in the sixth and seventh squares. Since forced-choice responses to squares 8 through 12 were not given, presumably due to lack of viewing time, it can only be inferred that the threshold lay at square 6 or higher. Tentative values of the apparent contrast and angular size of the sixth and seventh rectangles at the Laredo site at the time of the observation are plotted in figure 8.15-2. The solid line in the illustration represents the preflight visual performance of the pilot as measured in the training van and the dashed lines represent the and 2-siena limits of his visual performance. The positions of the plotted points indicate that his visual performance at the time of revolution 45 was within the statistical range of his preflight visual performance.
8.15.5 Conclusions
Experiment S-8/D.-13 appears to have achieved successfully both of its stated objectives. Data from the in-flight vision tester is complete and of high quality_ preliminary evaluation indicates that the visual performance of the astronauts was not degraded during the 8-day mission. Results from observation of the ground site near Laredo Texas appear to confirm that the visual performance of the pilot during space flight was within the statistical range of his preflight visual performance and that laboratory visual acuity data can be combined with environmental optical data to predict correctly the limiting visual capability of astronauts to discriminate small objects on the surface of the earth in daylight."
Gemini 5 Flown S-8/D-13 Checklist Page
This is the reverse of the before shown page. It indicates when the experiment should be conducted.
The annotations were done during the flight.
Due to some changes in the mission not all oberservation were made.
The Gemini 5 mission report describes the results of the experiment as follows:
"8.15.1 Objective
The first objective of experiment S-8/D-13 was to measure the visual acuity of the flight crew members before, during, and after long-duration space flights in order to ascertain the effects of a prolonged spacecraft environment. The second objective was to test the use of basic visual-acuity data combined with measured optical properties of ground objects and their natural lighting, the atmos- phere, and the spacecraft window to predict the limiting naked-eye visual capability of the flight crew to discriminate small objects on the surface of the earth in daylight.
8.15.2 Equipment
The experimental equipment consisted of an in-flight vision tester for testing visual acuity, an in-flight photometer to monitor the space- craft window s and test patterns at two ground observation sites.
8.15.2.1 In-flight vision tester.- The in-flight vision tester was a small, self-contained binocular optical device containing a transilluminated array of 96 high-contrast and low-contrast rectangles, half of which were oriented vertically in the field of view while the remainder were horizontal. Rectangle size, contrast, and orientation were randomized; the presentation was sequential, and the sequences were non-repetitive. Each rectangle was viewed singly at the center of a 10° adapting field the apparent luminance of which was approximately i00 foot-lamberts. Both members of the flight crew made forced- choice judgments of the orientation of each rectangle and indicated
their responses by punching holes in a record card. Optical alinement was accomplished by means of a bite-board equipped with the flight crew member's dental impression. Electrical power for illumination within the illumination was derived from the spacecraft.
8.15.2.2 In-flight photometer.- A photoelectric photometer was mounted near the lower right corner of the right hatch window to measure the amount of ambient light scattered by the window into the path of sight at the moment when observations of the ground test patterns were to be made. The photometer had a narrow (1.2°) circular field of view into the opening of a small black cavity a few inches away from the outside of the right hatch window. The photometric scale was linear and extended from 60 to 9000 foot-lamberts. Since the apparent luminance of the black cavity was always less than 60 foot-lamberts, any reading of the photometer was ascribable to ambient light scattered by the window. This information combined with data on the beam transmittance of the window and on the apparent luminance of the background squares in the ground array, enabled the contrast transmittance of the window at the moment of observation to be calculated.
8.15.2.3 Ground observation sites.- Ground observation sites were provided on the Gates Ranch 40 miles north of Laredo, Texas, and the Woodleigh Ranch 90 miles south of Carnarvon, Australia. At the Texas site, twelve 2000 by 2000 feet squares of plowed, graded, and raked soil were arranged in a 4 by 3 matrix. White rectangles of styrofoam-coated wallboard were laid out in each square. Their length decreased in a uniform logarithmic progression from 610 feet in the northwest corner (square number 1) to 152 feet in the southwest corner (square number 12) of the array. Each of the 12 rectangles was oriented in 1 of 4 positions (i.e., north-south, east-west, or diagonal) and the orientations were random, within the series of 12. Advance knowledge of the rectangle orientations were withheld from the flight crew since their task was to report the orientations. Provision was made for changing the rec- tangle orientations between passes and for adjusting their size in accordance with anticipated slant range, solar elevation, and the visual performance of the flight crew on preceding passes.
8.15.3 Procedure
Both of the flight crew members completed five or more preflight sessions in a laboratory training van during which they became experienced in psychophysical techniques and established physiological base- lines descriptive of their individual visual performance. The statistical fluctuations in that perfomance were established, providing a means by which the ground pattern observations could be interpreted.
8.15.4 Results
In-flight vision tests were to be performed once each once by each crew member. Ground observations were to be made by the pilot with the command pilot orienting the spacecraft as prescribed in the flight plan. The results of these tests, together with preflight and postflight test results, are shown in figure 8.15-1. Unfavorable cloud conditions caused some scheduled observations of the ground markings to be deleted. In the latter part of the mission, lack of thruster control made observation of the ground patterns impossible.
Quantitative observation of ground marking was achieved only once. This occurred at the ground observation site near Laredo, Texas, during revolution 48. Despite the fleeting nature of the observation, there exists a reasonable probability that the pilot correctly discriminated the rectangles in the sixth and seventh squares. Since forced-choice responses to squares 8 through 12 were not given, presumably due to lack of viewing time, it can only be inferred that the threshold lay at square 6 or higher. Tentative values of the apparent contrast and angular size of the sixth and seventh rectangles at the Laredo site at the time of the observation are plotted in figure 8.15-2. The solid line in the illustration represents the preflight visual performance of the pilot as measured in the training van and the dashed lines represent the and 2-siena limits of his visual performance. The positions of the plotted points indicate that his visual performance at the time of revolution 45 was within the statistical range of his preflight visual performance.
8.15.5 Conclusions
Experiment S-8/D.-13 appears to have achieved successfully both of its stated objectives. Data from the in-flight vision tester is complete and of high quality_ preliminary evaluation indicates that the visual performance of the astronauts was not degraded during the 8-day mission. Results from observation of the ground site near Laredo Texas appear to confirm that the visual performance of the pilot during space flight was within the statistical range of his preflight visual performance and that laboratory visual acuity data can be combined with environmental optical data to predict correctly the limiting visual capability of astronauts to discriminate small objects on the surface of the earth in daylight."